Polytetrafluoroethylene fibers have been found to be useful as a dental floss. A particularly useful polytetrafluoroethylene fiber is one that has been termed to be expanded. In U.S. Pat. No. 3,664,915, the term expanded is defined as a polytetrafluoroethylene that has a decreased specific gravity. The fiber undergoes processing, which can include heating and stretching, to produce a node and fibril structure in the fiber. Such fibers are useful as flosses, with the fibers of preferred interest being these fibers which have a tensile strength such that the fiber will not break during flossing, and in addition, where the fiber undergoes substantially no elongation during use as a floss. A stretched polytetrafluoroethylene fiber having these latter properties is preferred as a floss.
The use of polytetrafluoroethylene as a floss is discussed in U.S. Pat. No. 4,776,358. In that patent, there is discussed a floss consisting of a dentifrice between two layers of polytetrafluoroethylene. One problem with this floss is that it is not grippable. The floss material slips through a person's fingers. One solution to this problem was found in U.S. Pat. No. 5,033,488 and U.S. Pat. No. 5,209,251. This was to put a friction increasing coating onto the surface of the polytetrafluoroethylene fiber. The preferred coating is a wax, and in particular a microcrystalline wax. Other coating materials that would adhere to the polytetrafluoroethylene surface and that would increase the coefficient of friction are also described to be useful. These are useful flosses since they are grippable and shred resistant. However, they have some disadvantages.
One disadvantage is that some dental practitioners advise against using a coated floss and in particular a wax coated floss. There is a belief among such practitioners that this results in a wax build-up on a person's teeth. Another disadvantage is that this requires an additional manufacturing step. After the stretched polytetrafluoroethylene fiber is produced, it must be coated. There is the increased cost of a coating material and the coating procedure. The present floss does not have these disadvantages. It provides all of the benefits of a polytetrafluoroethylene fiber of being shred resistant and easily insertable into close inter dental spaces without these disadvantages. It solves the problem of a grippable polytetrafluoroethylene fiber that does not have a coating. This is accomplished by the structure of the fiber itself.